Apparatus having agitator for agitating fluid

ABSTRACT

An apparatus of a heat transfer circuit in which a heat transfer fluid with small particles circulates includes a container and an agitator. The container is located in a lower position of the apparatus in a vertical direction and defines a chamber where the heat transfer liquid passes when circulating in the heat transfer circuit. The agitator is located in the chamber to agitate the heat transfer fluid.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and claims priority to Japanese Patent Application No. 2010-138694 filed on Jun. 17, 2010, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an apparatus having an agitator for agitating a heat transfer fluid with small particles.

BACKGROUND OF THE INVENTION

A heat transfer fluid is used to absorb heat from a heat source and transfer the absorbed heat. For example, a heat transfer fluid disclosed in JP-A-2007-31520 or US 2010/0095911 corresponding to JP-A-2008-189901 is formed by adding nanoparticles with a diameter on the order of nanometers to a solvent to improve a heat conductivity of the heat transfer fluid.

Specifically, in JP-A-2007-31520, carbon nanotube of 0.05 wt % or more and cellulose derivative or its sodium salt are added to a solvent such as water or ethylene glycol. In US 2010/0095911, carbon nanotube and carboxymethylcellulose sodium salt are added to a solvent such as water or ethylene glycol.

There is a possibility that the nanoparticles can precipitate out of the solvent with time or due to the cessation of the flow of the heat transfer fluid. If the nanoparticles precipitate out of the solvent, the heat conductivity of the heat transfer fluid decrease.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention to provide an apparatus having an agitator for agitating a heat transfer fluid with small particles to prevent a decrease in a heat conductivity of the heat transfer fluid.

According to an aspect of the present invention, an apparatus of a heat transfer circuit in which a heat transfer fluid with small particles circulates includes a container and an agitator. The container is located in a lower position of the apparatus in a vertical direction and defines a chamber where the heat transfer liquid passes when circulating in the heat transfer circuit. The agitator is located in the chamber to agitate the heat transfer fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages will become more apparent from the following description and drawings in which like reference numerals depict like elements. In the drawings:

FIG. 1 is a block diagram of a heat transfer circuit including an apparatus having an agitator according to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating a detailed view of the agitator of the apparatus of FIG. 1;

FIGS. 3A-3D are diagrams illustrating a flow of a heat transfer fluid caused by the agitator;

FIG. 4 is a diagram illustrating an apparatus having an agitator according to a second embodiment of the present invention;

FIG. 5 is a block diagram of a heat transfer circuit including an apparatus having an agitator according to a third embodiment of the present invention;

FIG. 6 is a diagram illustrating an apparatus having an agitator according to a fourth embodiment of the present invention;

FIG. 7 is a block diagram of a heat transfer circuit including an apparatus having an agitator according to a fifth embodiment of the present invention;

FIG. 8 is a diagram illustrating a detailed view of the agitator of the apparatus of FIG. 7;

FIG. 9 is a diagram illustrating an agitator according to a modification of the fifth embodiment;

FIGS. 10A-10C are diagrams illustrating operations of an agitator according to a sixth embodiment of the present invention;

FIG. 11 is a diagram illustrating an agitator according to a seventh embodiment of the present invention, and

FIG. 12 is a diagram illustrating an agitator according to an eighth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

A heat transfer circuit 1 according to a first embodiment of the present invention is described below with reference to FIG. 1. A heat transfer fluid circulates in the heat transfer circuit 1 and transfers heat generated by a heat source such as an engine or a transmission apparatus of a vehicle to outside, thereby cooling the heat source. The heat transfer fluid includes a solvent and small particles having heat conductivity greater than that of the solvent. The particles are dispersed in the solvent so that the heat transfer fluid can have a high heat conductivity. Therefore, the heat transfer fluid can efficiently transfer the heat.

The solvent can carry the particles dispersed in the solvent. For example, the solvent can be water or organic material such as ethylene glycol or toluene. The solvent can be a single-component substance or a mixture of components.

Each particle dispersed in the solvent is very small, for example, on the order of micrometers or nanometers in size. For example, the particle can be a metal particle made of gold (Au), silver (Ag), copper (Cu), iron (Fe), or nickel (Ni). Alternatively, the particle can be an inorganic particle made of silicon (Si) or fluorine (F). Alternatively, the particle can be an oxide particle made of aluminum oxide (Al₂O₃), magnesium oxide (MgO), copper oxide (CuO), Ferric trioxide (Fe₂O₃), or titanium oxide (TiO). Alternatively, the particle can be a polymer particle made of carbon nanotube or resin.

The particle is not limited to a particular shape. For example, the particle can have a rod-like shape, a spherical shape, or a polyhedral shape. The rod-like shaped particle means a long particle having a large aspect ratio, which is a ratio of the long side (i.e., length) to the short side (i.e., width).

Referring to FIG. 1, the heat transport circuit 1 includes a central processing circuit (CPU) 2, a heat exchanger (HEX) 3, a radiator 4, a reserver tank 5, and a pump 6. The CPU 2, the heat exchanger 3, the radiator 4, the reserver tank 5, and the pump 6 are connected in a ring to form the heat transfer circuit 1. The CPU 2 is an example of a heat source.

Although not shown in the drawings, the heat exchanger 3 has a heat exchange plate and a pipe extending around the heat exchange plate. The heat transfer fluid passes the heat exchanger 3 by flowing through the pipe. The heat exchange plate is thermally connected to the CPU 2 so that heat generated by the CPU 2 can be transferred to the heat exchange plate. When the heat transfer fluid flows through the pipe, the heat transfer fluid comes into thermal contact with the heat exchange plate so that the heat transferred to the heat exchange plate can be absorbed by the heat transfer fluid. Thus, the CPU 2 can be cooled. In the heat exchanger 3, an inlet of the pipe is connected to the pump 6, and an outlet of the pipe is connected to the radiator 4.

The radiator 4 includes a core 43, a lower tank 41, and an upper tank 44. The core 43 has tubes and fins that are alternately arranged with the tubes. The tubes connect the lower tank 41 and the upper tank 44. The fins are in thermal contact with the tubes to increase the surface areas of the tubes. The lower tank 41 has an inlet pipe 42 connected to the heat exchanger 3. The heat transfer fluid flows from the heat exchanger 3 to the radiator 4 through the inlet pipe 42 and is collected in the lower tank 41. The heat transfer fluid collected in the lower tank 41 flows through the pipes and is collected in the upper tank 44. The upper tank 44 has an outlet pipe 45 connected to the reserver tank 5.

The reserver tank 5 is an auxiliary tank for storing the heat transfer fluid circulating in the heat transfer circuit 1. An inlet pipe 52 connected to the outlet pipe 45 of the radiator 4 is connected to a lower part of the reserver tank 5 in a vertical direction. An outlet pipe 53 connected to the pump 6 is connected to the reserver tank 5. It is noted that the output pipe 53 is located above the inlet pipe 52 in the vertical direction. The reserver tank 5 has a bottom container 51 in a lower position in the vertical direction.

The pump 6 is an electric pump and forces the heat transfer fluid to circulate in the heat transfer circuit 1. When the pump 6 is activated, the heat transfer fluid circulates in the heat transfer circuit 1 so as to cool the CPU 2. Specifically, the heat transfer fluid pumped by the pump 6 flows to the heat exchanger 3 and absorbs the heat generated by the CPU 2 through the heat exchange plate in the heat exchanger 3. Then, the heat transfer fluid flows to the radiator 4 so that the absorbed heat can be transferred to the radiator 4 by the heat transfer fluid. In the radiator 4, when the heat transfer fluid flows from the lower tank 41 to the upper tank 44 through the tubes of the core 43, the heat transfer fluid is cooled by dissipating the absorbed heat into the air passing through the tubes and the fins of the core 43. The heat transfer fluid cooled in the core 43 is collected in the upper tank 44, flows out to the reserver tank 5, and is sucked into the pump 6. The heat transfer fluid sucked into the pump 6 is pumped up to the heat exchanger 3, absorbs the heat generated by the CPU 2 in the heat exchanger 3, and then is cooled by dissipating the absorbed heat into the air in the radiator 4. In this way, when the pump 6 is in operation, the heat transfer fluid continuously circulates in the heat transfer circuit 1 and repeats absorption and dissipation of heat.

When the pump 6 is stopped, the flow of the heat transfer fluid is stopped. As a result, there is a possibility that the particles in the heat transfer fluid may solidify and precipitate out of the solvent. Since the precipitation of the particles occurs due to the fact that the heat transfer fluid is under the influence of gravity, it is difficult to completely prevent the precipitation. As mentioned previously, when the particles precipitate out of the solvent, the heat conductivity of the heat transfer fluid decreases compared to when the particles are dispersed in the solvent. Therefore, even when the pump 6 is reactivated under a condition where the particles precipitate out of the solvent, absorption of heat in the heat exchanger 3 and dissipation of heat in the radiator 4 are not suitably performed due to a decrease in the heat conductivity of the heat transfer fluid. As a result, a desired cooling performance cannot be obtained in the heat transfer circuit 1.

It is likely that the precipitate of the particles remains in the tubes and the containers of the apparatus of the heat transfer circuit 1. Specifically, the precipitate can exist in the inlet pipe 42, the outlet pipe 45, the inlet pipe 52, the output pipe 53, the lower tank 41 of the radiator 4, and the bottom container 51 of the reserver tank 5.

According to the first embodiment, an agitator 7 for agitating the heat transfer fluid is provided in the container that is located in a lower position in the vertical direction. Specifically, in an example shown in FIG. 1, the agitator 7 is provided in each of a chamber 71 of the lower tank 41 of the radiator 4 and a chamber 71 of a bottom container 51 of the reserver tank 5. That is, each of the radiator 4 and the reserver tank 5 is an apparatus having an agitator for agitating a heat transfer fluid with a solvent and small particles dispersed in the solvent to prevent the particles from precipitating out of the solvent.

FIG. 2 illustrates a detailed view of the lower tank 41 having the agitator 7. The lower tank 41 itself serves as the agitator 7. That is, the lower tank 41 and the agitator 7 are a single piece. The agitator 7 is configured as an oscillator for producing vortexes VA, VB in a jet of the heat transfer fluid issuing into the chamber 71 so as to swing the jet. The agitator 7 includes a chamber member (e.g., the lower tank 41) defining the chamber 71, and a nozzle (e.g., the inlet pipe 42) defining an inlet 72 to the chamber 71. It is noted that a height “a” of the inlet 72 is less than a height “H” of the chamber 71 in the vertical direction.

Operations of the agitator 7 shown in FIG. 2 are described below with reference to FIGS. 3A-3D. When the heat transfer fluid flows into the chamber 71 through the inlet 72, a jet of the heat transfer fluid issuing from the inlet 72 into the chamber 71 occurs due to a difference between the height “a” of the inlet 72 and the height “H” of the chamber 71. As indicated by a solid line in FIG. 3A, the jet of the heat transfer fluid issuing into the chamber 71 is deflected toward a lower inner surface of the chamber member due to the Coanda effect so that the jet can approach the lower inner surface of the chamber member as close as possible or be attached to the lower inner surface of the chamber member. Then, as indicated by a broken line in FIG. 3A, a clockwise vortex VA is produced between the jet and the lower inner surface of the chamber member, and a counter-clockwise vortex VB is produced between the jet and an upper inner surface of the chamber 71. At this time, pressure is less in the vortex VA than in the vortex VB. Therefore, as indicated by an arrow in FIG. 2 and FIG. 3A, a stream of the heat transfer fluid toward the vortex VA occurs near the inlet 72 of the chamber 71. That is, the stream of the heat transfer fluid circles from near the inlet 72 toward the lower inner surface of the chamber member.

Due to the circulating stream, as shown in FIGS. 3B and 3C, the jet, indicated by the solid line, moves away from the lower inner surface of the chamber member, the vortex VA disappears, and the vortex VB moves toward the inlet 72. Then, as shown in FIG. 3D, the jet, indicated by the solid line, is deflected toward an upper inner surface of the chamber member due to the Coanda effect so that the jet can approach the upper inner surface of the chamber member as close as possible or be attached to the upper inner surface of the chamber member. Thus, the vortexes VA, VB in FIG. 3D are symmetrically positioned relative to the vortexes VA, VB in FIG. 3A. Then, phenomena like those shown in FIGS. 3B and 3C occurs so that the state in the chamber 71 can return to FIG. 3A from FIG. 3D. In this way, when the heat transfer fluid flows into the chamber 71, the states shown in FIGS. 3A-3D are repeated. Such an oscillation phenomenon of the jet of the heat transfer fluid in the chamber 71 is caused by the ups and downs of the vortexes VA, VB that are located on opposite sides of the jet.

As described above, according to the first embodiment, at least one of the apparatus of the heat transfer circuit 1 for circulating the heat transfer fluid with the solvent and the small particles dispersed in the solvent includes the agitator 7 in a lower position of the container in the vertical direction.

In such an approach, even when the small particles precipitate out of the solvent due to the stop of the pump 6 and are deposited in the lower position of the apparatus in the vertical direction due to the gravity, the heat transfer fluid can be agitated by the agitator 7 so that the small particles can be dispersed in the solvent. Thus, the heat conductivity of the heat transfer fluid is maintained so that a desired heat transfer performance can be obtained.

Preferably, the agitator 7 can be provided in at least one of the radiator 4, the reserver tank 5, and the pipes 42, 45, 52, and 53. That is, the agitator 7 can be located in a position where it is likely that the precipitate of the small particles will occur. Thus, the heat transfer fluid can be effectively agitated by the agitator 7 so that the small particles can be dispersed in the solvent.

The agitator 7 is configured as an oscillator for producing vortexes in a jet of the heat transfer fluid issuing into the chamber 71 so as to swing the jet. Thus, the agitator 7 swings the heat transfer fluid in the chamber 71 during the circulation of the heat transfer fluid in the heat transfer circuit 1. Thus, the heat transfer fluid in the chamber 71 is agitated so that the precipitate of the small particles in the chamber 71 can be prevented.

The agitator 7 includes the chamber member defining the chamber 71 and the nozzle defining the inlet 72 for the heat transfer fluid to the chamber 71. The height “a” of the inlet 72 is less than the height “H” of the chamber 71 in the vertical direction so that the agitator 7 can serve as the oscillator. Since the container located in the lower position of the apparatus itself serves as the agitator 7, there is no need to add a separate agitator. Thus, manufacturing cost can be reduced.

Second Embodiment

An apparatus having an agitator 8 according to a second embodiment of the present invention is described below with reference to FIG. 4. According to the second embodiment, the agitator 8 is provided in a radiator 4A.

The agitator 8 is located in a lower position of a container of the apparatus in the vertical direction. As shown in FIG. 4, the agitator 8 includes a chamber 81 defined by a chamber member 41A and an inlet passage 82 defined by an inlet pipe 42A that is connected to an inlet 82 a to the chamber 81. It is noted that the chamber member 41A is a lower tank of the radiator 4A. That is, the lower tank of the radiator 4A and the agitator 8 are a single piece. The chamber member 41A has a cylindrical inner surface defining the inlet 82 a. The inlet passage 82 extends in a direction of the tangent to the cylindrical inner surface of the chamber member 41A. When the heat transfer fluid enters the chamber 81 through the inlet passage 82 of the inlet pipe 42A, the heat transfer fluid flows along the cylindrical inner surface of the chamber member 41A. Thus, in the chamber 81, the heat transfer fluid moves from the outside to the inside to form a circle. In this way, a swirling flow of the heat transfer fluid is produced in the chamber 81.

As described above, according to the second embodiment, the agitator 8 includes the chamber 81 and the inlet passage 82. The chamber member 41A defining the chamber 81 has the cylindrical inner surface, and the inlet passage 82 extends in the direction of the tangent to the cylindrical inner surface of the chamber member 41A. In such an approach, the heat transfer fluid flowing into the chamber 81 through the inlet passage 82 forms a swirling flow in the chamber 81. Thus, the heat transfer fluid in the chamber 81 is agitated so that the precipitate of the small particles in the chamber 81 can be prevented.

Third Embodiment

An apparatus having an agitator 9 according to a third embodiment of the present invention is described below with reference to FIG. 5. According to the third embodiment, the agitator 9 is provided in at least one of a radiator 4B and a reserver tank 5B.

The agitator 9 is configured as an ultrasonic vibrator and ultrasonically vibrates the heat transfer fluid collected in chambers 41 a, 51 a in a lower position of containers (i.e., the lower tank 41, the bottom container 51) of the radiator 4B and the reserver tank 5B. The agitator 9 includes an ultrasonic transducer and a vibrating member joined to the ultrasonic transducer. The ultrasonic transducer is an electronic device for converting electric power supplied from a power source such as a battery into mechanical ultrasonic vibrations. The mechanical ultrasonic vibrations are transmitted to the vibrating member so that a tip of the vibrating member can ultrasonically vibrate in its length direction. The ultrasonic vibrations are transmitted to the heat transfer fluid around the vibrating member so that the heat transfer fluid in the chambers 41 a, 51 a can be agitated.

As described above, according to the third embodiment, the agitator 9 is configured as an ultrasonic vibrator and ultrasonically vibrates the heat transfer fluid collected in the chambers 41 a, 51 a during the circulation of the heat transfer fluid in the heat transfer circuit 1. Thus, the heat transfer fluid in the chambers 41 a, 51 a is agitated so that the precipitate of the small particles in the chambers 41 a, 51 a can be prevented.

Fourth Embodiment

An apparatus having an agitator 10 according to a fourth embodiment of the present invention is described below with reference to FIG. 6. According to the fourth embodiment, the agitator 10 is provided in a radiator 4C.

The agitator 10 is located in a lower position of a container of the apparatus in the vertical direction. As shown in FIG. 6, the agitator 10 is located in a chamber 41 a of the lower tank 41 of the radiator 4C. The agitator 10 includes a rotator 101, a driven portion 102, and a rotating shaft 103. The rotator 101 rotates when the driven portion 102 or the rotating shaft 103 are driven. The rotator 101 is coupled to the driven portion 102 through the rotating shaft 103. The rotator 101 is positioned below the driven portion 102 in the vertical direction.

As shown in FIG. 6, the driven portion 102 is located at almost the same height as the inlet pipe 42 that is connected to an upper portion of the lower tank 41. The rotator 101 is located in a lower position in the lower tank 41. For example, the driven portion 102 can be an impeller or radially-arranged blades. The driven portion 102 is driven by the heat transfer fluid flowing into the chamber 41 a so that the rotating shaft 103 can rotate. The rotator 101 rotates with the rotating shaft 103 so that the heat transfer fluid in the lower position in the chamber 41 a can be agitated.

As described above, according to the fourth embodiment, the agitator 9 includes the rotator 101 in the chamber 41 a. Thus, the heat transfer fluid in the chamber 41 a is agitated so that the precipitate of the small particles in the chamber 41 a can be prevented.

The rotator 101 rotates with the driven portion 102 that is driven by pressure of the heat transfer fluid flowing into the chamber 41 a. In such an approach, the rotator 101 rotates without an external power source so that the heat transfer fluid in the chamber 41 a can be efficiently agitated.

Alternatively, the driven portion 102 can be driven by using an external power source. For example, the driven portion 102 can be driven by power supply from a starter of an engine or a motor of the vehicle. The driven portion 102 can be driven by power generated when a door of the vehicle is opened and closed. Alternatively, a mechanical rotating power can be applied directly to the rotator 101 or the rotating shaft 103.

Fifth Embodiment

An apparatus having an agitator 11 according to a fifth embodiment of the present invention is described below with reference to FIGS. 7 and 8. According to the fifth embodiment, the agitator 11 is provided in at least one of a radiator 4D and a reserver tank 5D.

The agitator 11 includes a cylindrical column 111 located in a chamber 112 in a lower position of containers (i.e., the lower tank 41, the bottom container 51) of the radiator 4D and the reserver tank 5D. The cylindrical column 111 is positioned so that the heat transfer fluid flowing into the chamber 112 can hit the cylindrical column 111. For example, the cylindrical column 111 can be positioned near the inlet to the chamber 112. As shown in FIG. 8, when the heat transfer fluid hits the cylindrical column 111, a Karman vortex is created on the downstream side of the cylindrical column 111.

In an example shown in FIGS. 7 and 8, an axis of the cylindrical column 111 is in a horizontal direction perpendicular to the vertical direction. The axis of the cylindrical column 111 is not limited to the horizontal direction. For example, the axis of the cylindrical column 111 can be in the vertical direction.

In the example shown in FIGS. 7 and 8, one cylindrical column 111 is provided in the chamber 112. Alternatively, two or more cylindrical columns 112 can be provided in the chamber 112.

As described above, according to the fifth embodiment, the agitator 11 includes the cylindrical column 111 in the chamber 112. Thus, the heat transfer fluid in the chamber 112 is agitated so that the precipitate of the small particles in the chamber 112 can be prevented.

Sixth Embodiment

An apparatus having an agitator 12 according to a sixth embodiment of the present invention is described below with reference to FIGS. 10A-10C. According to the sixth embodiment, the agitator 12 is provided in the radiator 4E.

The agitator 12 is located in the chamber 41 a of the lower tank 41, which is located in a lower position of the radiator 4E in the vertical direction. The agitator 12 includes a thin film 122 having a fixed end 121 on one side and a free end on the other side. The fixed end 121 is located at a predetermined height from a bottom of the lower tank 41. When the heat transfer fluid flows into the chamber 41 a, the film 122 floats in the heat transfer fluid depending on its specific gravity and elasticity.

As shown in FIG. 10A, in normal operation conditions where the heat transfer fluid continuously flows into the chamber 41 a, the film 122 is stretched along a direction of flow of the heat transfer fluid. Then, when the heat transfer fluid stops circulating in the heat transfer circuit 1 due to, for example, deactivation of the pump 6, the small particles start to precipitate out of the solvent. As a result, as shown in FIG. 10B, a precipitate D of the small particles on the film 122 occurs, and the film 122 is deformed due to the weight of the precipitate D so that the free end of the film 122 can hang down on the bottom of the chamber 41 due to its elasticity. Then, when the pump 6 is reactivated, the heat transfer fluid restarts to circulate in the heat transfer circuit 1 and thus flows into the chamber 41 a. As a result, as shown in FIG. 10C, the film 122 is blown up by pressure of the heat transfer fluid so that the precipitate D on the film 122 can be dispersed in the solvent of the heat transfer fluid.

As described above, according to the sixth embodiment, the agitator 12 includes the film 122 located in the chamber 41 a. When the small particles precipitate out of the solvent due to the stop of the circulation of the heat transfer fluid in the heat transfer circuit 1, the precipitate D of the small particles occurs on the film 122. Therefore, when the circulation of the heat transfer fluid is restarted, the film 122 is blown up by the heat transfer fluid flowing into the chamber 41 a so that the precipitate D on the film 122 can be dispersed. Thus, the heat transfer fluid in the chamber 41 a is agitated so that the precipitate of the small particles in the chamber 41 a can be prevented. The ability of the agitator 12 to disperse the precipitate can be adjusted by adjusting the size, the hardness, the elasticity, and/or the like.

It is preferable that the film 122 be made of a shape-memory material. For example, the film 122 can return to its original shape according to temperature. When the film 122 returns to its original shape, the precipitate on the film 122 is flipped up. In this way, the film 122 can disperse the precipitate thereon by itself. Thus, the ability of the agitator 12 to disperse the precipitate can be improved.

Seventh Embodiment

An apparatus having an agitator 13 according to a seventh embodiment of the present invention is described below with reference to FIG. 11. According to the seventh embodiment, the agitator 13 is provided in a radiator 4F.

As shown in FIG. 11, the agitator 13 includes a chamber 131 defined by the lower tank 41 located in the lower position of the radiator 4F and an inlet passage 132 connected to the chamber 131. The inlet passage 132 extends obliquely downward toward the chamber 131 in the vertical direction so that the heat transfer fluid flowing into the chamber 131 through the inlet passage 132 can move toward the bottom of the chamber 131. Thus, the heat transfer fluid near the bottom of the chamber 131 is agitated so that the precipitate D on the bottom of the chamber 131 can be dispersed.

As described above, according to the seventh embodiment, the agitator 13 includes the chamber 131 and the inlet passage 132 connected to the chamber 131 in such a manner the inlet passage extends obliquely downward toward the chamber 131. In such an approach, the heat transfer fluid flowing into the chamber 131 through the inlet passage 132 moves toward the bottom of the chamber 131. Thus, the heat transfer fluid near the bottom of the chamber 131 is agitated so that the precipitate Don the bottom of the chamber 131 can be prevented. Since the precipitate D is likely to occur on the bottom of the chamber 131, the agitator 13 can effectively disperse the precipitate D.

Eighth Embodiment

An apparatus having an agitator 14 according to an eighth embodiment of the present invention is described below with reference to FIG. 12. According to the eighth embodiment, the agitator 14 is provided in a radiator 4G.

As shown in FIG. 12, the agitator 14 includes a chamber 141 defined by a lower tank 41G located in the lower position of the radiator 4G and an inlet passage 142 connected to the bottom of the chamber 141 in such a manner that the heat transfer fluid flows upward in the chamber 141 like a fountain flow. Thus, the heat transfer fluid near the bottom of the chamber 141 is agitated so that the precipitate D on the bottom of the chamber 141 can be dispersed.

As described above, according to the eighth embodiment, the agitator 14 includes the chamber 141 and the inlet passage 142 connected to the bottom of the chamber 141. In such an approach, the heat transfer fluid near the bottom of the chamber 131 is agitated so that the precipitate D on the bottom of the chamber 141 can be prevented. Since the precipitate D is likely to occur on the bottom of the chamber 141, the agitator 14 can effectively disperse the precipitate D.

Modifications

The embodiments described above can be modified in various ways, for example, as follows.

The solvent of the heat transfer fluid can be an organic solvent such as hexane, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran, dichloromethane, acetone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, butanol acetate, 2-propanol, 1-propanol, methanol, ethanol, or formic acid.

The solvent can be a mixture of two components. In this case, it is preferable that one component have a freezing-point depression effect. For example, the solvent can be formed by adding a freezing-point depressant to water. For example, the freezing-point depressant can be potassium acetate or sodium acetate. In such an approach, a freezing-point of the heat transfer fluid is reduced so that the heat transfer fluid can be used even in cold climates. Further, addition agents such as a rust inhibitor and an antioxidant can be added to the solvent as needed.

In the first embodiment, the chamber 71 has a cubic shape. The chamber 71 is not limited to the cubic shape. For example, the chamber 71 can have a cylindrical shape or an oval shape. Although the inlet 72 of the chamber 71 has a rectangular cross-section, the inlet 72 is not limited to the rectangular cross-section. For example, the inlet 72 can have a circular cross-section, an ellipsoidal cross-section, or a semicircular cross-section.

The embodiments described above can be combined in various ways as needed.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims. 

1. An apparatus of a heat transfer circuit in which a heat transfer fluid with a solvent and a plurality of particles dispersed in the solvent circulates to transfer heat generated by a heat source, the solvent being water or organic solvent, the apparatus comprising: a container located in a lower position of the apparatus in a vertical direction and defining a chamber where the heat transfer liquid passes to circulate in the heat transfer circuit; and an agitator located in the chamber and configured to agitate the heat transfer fluid.
 2. The apparatus according to claim 1, wherein the apparatus is a heat exchanger, a reserver tank, or a pipe of the heat transfer circuit.
 3. The apparatus according to claim 1, wherein the agitator produces a vortex in a jet of the heat transfer liquid issuing into the chamber in order to shake the jet.
 4. The apparatus according to claim 3, wherein the container and the agitator are a single piece, the container defines an inlet to the chamber, and a height of the inlet is less than a height of the chamber in the vertical direction so that the container serves as the agitator.
 5. The apparatus according to claim 1, wherein the container and the agitator are a single piece, the container has a cylindrical inner surface defining an inlet to the chamber, and the inlet extends in a direction of the tangent to the cylindrical inner surface of the container so that the container serves as the agitator.
 6. The apparatus according to claim 1, wherein the agitator ultrasonically vibrates the heat transfer fluid.
 7. The apparatus according to claim 1, wherein the agitator includes a driven portion and a rotator that rotates with the driven portion.
 8. The apparatus according to claim 7, wherein the rotator is positioned below the driven portion in the vertical direction, and the driven portion is driven by the heat transfer liquid flowing into the chamber.
 9. The apparatus according to claim 7, wherein the driven portion is driven by power supply from a starter of an engine or a motor of a vehicle.
 10. The apparatus according to claim 7, wherein the driven portion is driven by power generated when a door of a vehicle is opened and closed.
 11. The apparatus according to claim 1, wherein the agitator includes a cylindrical column, and the cylindrical column produces a Karman vortex when the heat transfer fluid flowing into the chamber hits the cylindrical column.
 12. The apparatus according to claim 1, wherein the agitator includes a film having a fixed end on one side and a free end on the other side, and the free end of the film floats in the heat transfer fluid when the heat transfer fluid flows into the chamber.
 13. The apparatus according to claim 1, wherein the agitator includes an inlet passage for the heat transfer fluid to the chamber, and the inlet passage extends obliquely downward toward the chamber.
 14. The apparatus according to claim 1, wherein the agitator includes an inlet passage for the heat transfer fluid to the chamber, and the inlet passage is connected to a bottom of the container in such a manner that the heat transfer fluid flows upward in the chamber. 